Boneyard Tools

Rate of Climb and Time to Climb Calculator

Work out how long a climb will take and how steep it is. Enter the altitude you still need to gain and your rate of climb in feet per minute to get the time to climb, then add a groundspeed to get the climb gradient in feet per nautical mile for crossing obstacles and meeting departure requirements.

How to calculate time to climb

  1. Enter the altitude you need to gain in feet.
  2. Enter your rate of climb in feet per minute.
  3. Add a groundspeed to also get the climb gradient in feet per nautical mile.

Examples

Climb to cruise

Gain 7000 ft at 700 fpm
10 minutes to climb

Climb gradient

700 fpm at 120 kt groundspeed
350 ft per nautical mile

Frequently asked questions

How is time to climb calculated?

Time to climb equals the altitude to gain divided by the rate of climb. Gaining 7000 feet at 700 feet per minute takes 10 minutes.

How is climb gradient calculated?

Climb gradient in feet per nautical mile equals the rate of climb divided by groundspeed, times 60. At 700 feet per minute and 120 knots that is 350 feet per nautical mile.

Why does climb gradient matter?

Departure procedures and obstacle clearance are often stated as a required gradient in feet per nautical mile. Comparing your gradient to the requirement shows whether you can make it.

How does groundspeed affect the gradient?

For the same rate of climb, a higher groundspeed means you cover more distance per foot gained, so the gradient is shallower. A headwind lowers groundspeed and steepens the gradient.

Is rate of climb constant during a climb?

No. Rate of climb falls as you go higher because the air is thinner and engine power drops. Use a planning figure for the altitude band you expect, or break the climb into steps.

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